On my Razer Blade 15, I’m unable to turn off Optimus.

The “GPU Mode” setting in Synapse refers me to the “NVIDIA laptop display mode”:

When I click the link, a popup on the lower right of my screen shows that “Optimus” is enabled (the icons are not clickable):

I then click “Manage display mode settings”, which takes me to this screen, which shows that “Optimus” is enabled, but the other options are grayed out and non-selectable:

Why are these options grayed out and not selectable? I’d like to turn off Optimus. How do I do it?